969 resultados para core plant role


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Although uncertainty is a fundamental human experience, professionals in the career field have largely overlooked the role that it plays in people's careers. The changed nature of careers has resulted in people experiencing increased uncertainty in their career that is beyond the uncertainty experienced in their job. The author explores the role of uncertainty in people's experience of their careers and examines the implications for career counseling theory and practice. A review of the career theory and career counseling literature indicates that although contemporary approaches have been offered to respond to the changed nature of career, none of the approaches have identified uncertainty as a core part of individuals' experience of their career. The broader literature on uncertainty is then reviewed at the societal, organizational, and individual levels.

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Leaf expansion and xylem cytokinin concentration ([X-CK]) decrease in response to nitrogen (N) deprivation. Debate continues over cause, effect, and correlation. Supporting studies provide, at best, correlative evidence that [X-CK] controls leaf growth in response to N-deprivation, while dissenting studies indicate that leaf growth responses to N can be independent of changes in X-CK supply to leaves. A model is proposed to evaluate the physiological significance to leaf growth of changes in plant and environment N concentrations, and plant CK concentrations.

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The degree to which Southern Hemisphere climatic changes during the end of the last glacial period and early Holocene (30-8 ka) were influenced or initiated by events occurring in the high latitudes of the Northern Hemisphere is a complex issue. There is conflicting evidence for the degree of hemispheric 'teleconnection' and an unresolved debate as to the principle forcing mechanism(s). The available hypotheses are difficult to test robustly, however, because the few detailed palaeoclimatic records in the Southern Hemisphere are widely dispersed and lack duplication. Here we present climatic and environmental reconstructions from across Australia, a key region of the Southern Hemisphere because of the range of environments it covers and the potentially important role regional atmospheric and oceanic controls play in global climate change. We identify a general scheme of events for the end of the last glacial period and early Holocene but a detailed reconstruction proved problematic. Significant progress in climate quantification and geochronological control is now urgently required to robustly investigate change through this period. Copyright (c) 2006 John Wiley & Sons, Ltd.

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Common bean (Phaseolus vulgaris L.), an annual diploid (2n=2x=22) species (Maréchal 1970; Delgado Salinas 1985), is adapted to mild temperatures (18°C to 35°C) and grown worldwide in a broad range of environments and in diverse production systems. Common bean is grown for its green leaves, green pods, and green and dry seeds. Dry leaves, threshed pods and stalks are fed to animals and used as fuel for cooking, especially in the developing countries of Africa and Asia (Singh 1991).

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Animals and plants in temperate regions must adapt their life cycle to pronounced seasonal variation. The research effort that has gone into studying these cyclical life history events, or phenological traits, has increased greatly in recent decades. As phenological traits are often correlated to temperature, they are relevant to study in terms of understanding the effect of short term environmental variation as well as long term climate change. Because of this, changes in phenology are the most obvious and among the most commonly reported responses to climate change. Moreover, phenological traits are important for fitness as they determine the biotic and abiotic environment an individual encounters. Fine-tuning of phenology allows for synchronisation at a local scale to mates, food resources and appropriate weather conditions. On a between-population scale, variation in phenology may reflect regional variation in climate. Such differences can not only give insights to life cycle adaptation, but also to how populations may respond to environmental change through time. This applies both on an ecological scale through phenotypic plasticity as well as an evolutionary scale through genetic adaptation. In this thesis I have used statistical and experimental methods to investigate both the larger geographical patterns as well as mechanisms of fine-tuning of phenology of several butterfly species. The main focus, however, is on the orange tip butterfly, Anthocharis cardamines, in Sweden and the United Kingdom. I show a contrasting effect of spring temperature and winter condition on spring phenology for three out of the five studied butterfly species. For A. cardamines there are population differences in traits responding to these environmental factors between and within Sweden and the UK that suggest adaptation to local environmental conditions. All populations show a strong negative plastic relationship between spring temperature and spring phenology, while the opposite is true for winter cold duration. Spring phenology is shifted earlier with increasing cold duration. The environmental variables show correlations, for example, during a warm year a short winter delays phenology while a warm spring speeds phenology up. Correlations between the environmental variables also occur through space, as the locations that have long winters also have cold springs. The combined effects of these two environmental variables cause a complex geographical pattern of phenology across the UK and Sweden. When predicting phenology with future climate change or interpreting larger geographical patterns one must therefore have a good enough understanding of how the phenology is controlled and take the relevant environmental factors in to account. In terms of the effect of phenological change, it should be discussed with regards to change in life cycle timing among interacting species. For example, the phenology of the host plants is important for A. cardamines fitness, and it is also the main determining factor for oviposition. In summary, this thesis shows that the broad geographical pattern of phenology of the butterflies is formed by counteracting environmental variables, but that there also are significant population differences that enable fine-tuning of phenology according to the seasonal progression and variation at the local scale.

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Analysing investments in ISs in order to maximise benefits has become a prime concern, especially for private corporations. No formula of equilibrium exists that could link the injected amounts and accrued returns. The relationship is simply not straightforward. This thesis is based upon empirical work which involved sketching organisational ethnographies (four organographies and a sectography) into the role and value of information systems in Jordanian financial organisations. Besides deciphering the map of impacts, it explains the attributions of the variations in the impacts of ISs which were found to be related to the internal organisational processes: culturally and politically specific considerations, economically or technically rooted factors and environmental factors. The research serves as an empirical attempt to test out the applicability of adopting the interpretive paradigm to researching organisations in a developing country. The fieldwork comprised an exploratory stage, a detailed investigation of four case studies and a survey stage encompassing 16 organisations. Primary and secondary data were collected from multiple sources using a range of instruments. The evidence highlights the fact that little long term strategic planning was pursued; the emphasis was more focused on short term planning. There was no noticeable adoption of any strategic fit principle linking IS strategy to the corporate strategy. In addition, the benefits obtained were mostly intangible. Although ISs were central to the work of the organisations surveyed as the core technology, they were considered as tools or work enablers rather than weapons for competitive rivalry. The cultural specificity of IS impacts was evident and the cultural and political considerations were key factors in explaining the attributions of the variations in the impacts of ISs in JFOs. The thesis confirms that measuring the benefits of ISs is the problematic. However, in order to gain more insight, the phenomenon of "the use of ISs" has to be studied within its context.